What does solubility mean?
process of dissolving a solute into a solvent
process of dissolving a solvent into a solute
process of determining the amount of solute a solvent will hold
process of determining the ratio of solute to solvent

process of dissolving a solute into a solvent

Explanation:

Solubility is the term that we used to make reference to the ability of a certain substance to be dissolve into another, the substance that is dissolved is called a solute and the substance that the solute dissolves in is called a solvent, so the best answer would be proccess of dissolving a solute in a solvent.

let that person have a turn to speak : )